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十七、Spring Boot使用Thymeleaf模版引擎以及语

十七、Spring Boot使用Thymeleaf模版引擎以及语

作者: 木石前盟Caychen | 来源:发表于2019-04-25 14:38 被阅读0次

    1、模版引擎

    JSP,Velocity,Freemarker,Thymeleaf...

    模版引擎.png

    Spring Boot推荐的模版引擎:Thymeleaf

    2、引入Thymeleaf依赖

    <!-- 修改Spring Boot的默认版本 -->
    <thymeleaf.version>3.0.9.RELEASE</thymeleaf.version>
    <!-- 布局功能的支持程序
          thymeleaf3 对应layout2版本
          thymeleaf2 对应layout1版本
       -->
    <thymeleaf-layout-dialect.version>2.2.2</thymeleaf-layout-dialect.version>
    
    <!-- thymeleaf模版引擎 -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>
    

    3、Thymeleaf的使用&语法

    ThymeleafProperties配置类:

    @ConfigurationProperties(prefix = "spring.thymeleaf")
    public class ThymeleafProperties {
        //默认编码
        private static final Charset DEFAULT_ENCODING = Charset.forName("UTF-8");
        //文档类型
        private static final MimeType DEFAULT_CONTENT_TYPE = MimeType.valueOf("text/html");
        //模版位置
        public static final String DEFAULT_PREFIX = "classpath:/templates/";
        //模版后缀
        public static final String DEFAULT_SUFFIX = ".html";
    
        private boolean checkTemplate = true;
    
        private boolean checkTemplateLocation = true;
    
        private String prefix = DEFAULT_PREFIX;
    
        private String suffix = DEFAULT_SUFFIX;
    
        private String mode = "HTML5";
    
        private Charset encoding = DEFAULT_ENCODING;
    
        private MimeType contentType = DEFAULT_CONTENT_TYPE;
        //缓存
        private boolean cache = true;
    
        private Integer templateResolverOrder;
    
        private String[] viewNames;
    
        private String[] excludedViewNames;
    
        private boolean enabled = true;
        
        //other code...
    }
    

    只要把模版html放置在classpath:/templates/目录下,thymeleaf就会自动渲染。

    4、使用Thymeleaf:

    (1)、导入thymeleaf的名称空间:

    <html lang="en" xmlns:th="http://www.thymeleaf.org"></html>
    

    ​ (2)、thymeleaf语法:

    <!DOCTYPE html>
    <html lang="en" xmlns:th="http://www.thymeleaf.org">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
    </head>
    <body>
        <div th:text="${hello}">这里是原来的文本!</div>
    </body>
    </html>
    

    ​ (3)、语法规则:

    ​ i)、th:text:改变当前元素里面的文本内容

    th:任意html属性:用来替换原生html属性的值,例如id换成th:id, class换成th:class等等。

    thymeleaf语法规则.png

    ​ ii)、表达式:

    Simple expressions:(表达式语法)
        Variable Expressions: ${...}:获取变量值,OGNL表达式
            1)、获取对象的属性、调用方法
            2)、使用内置的基本对象
               #ctx : the context object.
                #vars: the context variables.
                #locale : the context locale.
                #request : (only in Web Contexts) the HttpServletRequest object.
                #response : (only in Web Contexts) the HttpServletResponse object.
                #session : (only in Web Contexts) the HttpSession object.
                #servletContext : (only in Web Contexts) the ServletContext object.
             3)、内置的工具对象
                #execInfo : information about the template being processed.
                #messages : methods for obtaining externalized messages inside variables expressions, in the same way as they
                would be obtained using #{…} syntax.
                #uris : methods for escaping parts of URLs/URIs
                #conversions : methods for executing the configured conversion service (if any).
                #dates : methods for java.util.Date objects: formatting, component extraction, etc.
                #calendars : analogous to #dates , but for java.util.Calendar objects.
                #numbers : methods for formatting numeric objects.
                #strings : methods for String objects: contains, startsWith, prepending/appending, etc.
                #objects : methods for objects in general.
                #bools : methods for boolean evaluation.
                #arrays : methods for arrays.
                #lists : methods for lists.
                #sets : methods for sets.
                #maps : methods for maps.
                #aggregates : methods for creating aggregates on arrays or collections.
                #ids : methods for dealing with id attributes that might be repeated (for example, as a result of an iteration)
                
        Selection Variable Expressions: *{...}:选择表达式,跟${}功能类似
            补充功能:配合th:object进行使用
                <div th:object="${session.user}">
                    <p>Name: <span th:text="*{firstName}">Sebastian</span>.</p>
                    <p>Surname: <span th:text="*{lastName}">Pepper</span>.</p>
                    <p>Nationality: <span th:text="*{nationality}">Saturn</span>.</p>
                 </div>
                 
        Message Expressions: #{...}:获取国际化内容
        Link URL Expressions: @{...}:定义URL链接
            例子:@{/order/process(execId=${execId},execType='FAST')}
            
        Fragment Expressions: ~{...}:片段引用表达式
            
    Literals:
        Text literals: 'one text' , 'Another one!' ,…
        Number literals: 0 , 34 , 3.0 , 12.3 ,…
        Boolean literals: true , false
        Null literal: null
        Literal tokens: one , sometext , main ,…
        
    Text operations:
        String concatenation: +
        Literal substitutions: |The name is ${name}|
        Arithmetic operations:
        Binary operators: + , - , * , / , %
        Minus sign (unary operator): -
        
    Boolean operations:
        Binary operators: and , or
        Boolean negation (unary operator): ! , not
        
    Comparisons and equality:
        Comparators: > , < , >= , <= ( gt , lt , ge , le )
        Equality operators: == , != ( eq , ne )
        
    Conditional operators:
        If-then: (if) ? (then)
        If-then-else: (if) ? (then) : (else)
        Default: (value) ?: (defaultvalue)
        
    Special tokens:
        No-Operation: _
    

    ​ iii)、thymeleaf公共页面元素抽取:

    ​ 1)、抽取公共片段

    <div th:fragment="copy">
        &copy; 版权所有
    </div>
    

    ​ 2)、引入公共片段

    <div th:insert="~{footer :: copy}"></div>
    

    ~{templatename :: #selectorId} 表示:模版名::#选择器id

    代码片段
    <div id="copy-section">
        &copy; 2011 The Good Thymes Virtual Grocery
    </div>
    
    插入片段
    <div th:insert="~{footer :: #copy-section}"></div>
    

    ~{templatename :: fragmentname} 表示:模版名::片段名

    代码片段
    <div th:fragment="copy">
        &copy; 2011 The Good Thymes Virtual Grocery
    </div>
    
    插入片段
    <div th:insert="~{footer :: copy}"></div>
    

    ​ 3)、默认效果:insert的功能片段会被插入到div标签中。

    如果使用th:insert等属性进行引入,可以不用写~{},可以直接写templatename::#selectorId/fragmentname。

    但是如果是行内写法,必须加上~{}, 如[[~{}]]。

    三种引入公共片段的th属性:

    th:insert:将公共片段整个插入到声明引入的元素中

    th:replace:将声明引入的元素替换为公共片段

    th:include:将被引入的片段的内容包含到引入的元素中

    代码片段
    <footer th:fragment="copy">
        &copy; 版权所有
    </footer>
    
    引入方式
    <div th:insert="~{footer::copy}"></div>
    <div th:replace="~{footer::copy}"></div>
    <div th:include="~{footer::copy}"></div>
    
    实际效果:
    th:insert效果
    <div>
        <footer>
            &copy; 版权所有
        </footer>
    </div>
    
    th:replace效果
    <footer>
        &copy; 版权所有
    </footer>
    
    th:include效果
    <div>
        &copy; 版权所有
    </div>
    

    ​ (4)、在引入代码片段的时候,可以使用传递参数的方式,这样在代码片段中就可以使用传递过来的参数。

    <div th:fragment="frag">
    ...
    </div>
    
    <div th:replace="::frag (onevar=${value1},twovar=${value2})">
    

    <div th:fragment="frag (onevar,twovar)">
    <p th:text="${onevar} + ' - ' + ${twovar}">...</p>
    </div>
    
    <div th:replace="::frag (${value1},${value2})">...</div>
    使用命名参数时顺序不重要
    <div th:replace="::frag (onevar=${value1},twovar=${value2})">...</div>
    <div th:replace="::frag (twovar=${value2},onevar=${value1})">...</div>
    

    比如,在templates/commons/bar.html中定义了如下代码片段

    <nav id="sidebar">
        <a class="nav-link" th:class="${activeUrl == 'main' ? 'nav-link active' : 'nav-link'}" ...> 
            ...
        </a>
    </nav>
    

    在引入该代码片段的时候,可以使用传递参数的方式。

    <div th:replace="commons/bar::#sidebar(activeUrl='main')">...</div>
    或
    <div th:replace="commons/bar::#sidebar(activeUrl='emps')">...</div>
    

    至于其他Thymeleaf语法可以参考Thymeleaf官网http://www.thymeleaf.org

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